1. Field of the Invention
The present invention relates to a ball screw device, and more particularly to a ball screw device having a lubricating structure for effectively applying or supplying grease or oil to lubricate the ball screw device.
2. Description of the Prior Art
Typical ball screw devices comprise a ball nut rotatably and/or moveably engaged onto a screw shaft, and a number of balls or rollers or rolling members disposed or engaged between the ball nut and the screw shaft, for allowing the ball nut to be smoothly rotated and/or moved relative to the screw shaft.
Normally, the ball nut may be rotated and/or moved in a great speed relative to the screw shaft, such that grease or oil is required to be applied or supplied into the rolling members and the space defined between the ball nut and the screw shaft, for lubricating the ball screw device.
However, a precise sealing structure should be formed and provided between the ball nut and the ball screw, for preventing the grease or oil from flowing out of the ball nut and the screw shaft, such that a complicated and an accurate structure should be arranged between the ball nut and the screw shaft, to suitably retain the balls or rollers or rolling members and the grease or oil between the ball nut and the screw shaft.
U.S. Pat. No. 6,451,744 to Chang discloses one of the typical bushing assemblies including an inbuilt lubricating member provided therein and engaged between the ball nut and the screw shaft, for lubricating the ball nut and the screw shaft. However, the inbuilt lubricating member may have a good chance to be worn out after use, such the lubrication between the ball nut and the screw shaft may be become failure.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ball screw devices for such as machine tools or the like.